This invention relates to an open-end spinning rotor assembly having a rotor (rotor disk) which is provided with a rotor support shaft which serves for the radial bearing and the end of which is provided with a supporting element for the axial support against a step bearing.
In rotor spinning machines, open-end spinning rotors are wearing parts which must be replaced after a certain operating time of the machine. Previously, the rotor constituted the component part that had to be exchanged because it was worn out. However, coatings were developed by means of which the rotor achieve such a service life that today the rotor is no longer worn out first but rather the rotor support shaft. Particularly at its end which is supported on the step bearing in the axial direction, this shaft is worn to such an extent that it is shortened so that the rotor changes its axial position. Per se, it is possible to adjust the individual spinning rotors in the axial direction by means of an adjustment of the step bearing. However, in practice, this is not accepted as a solution to the wearing problem because the requirement exists that the spinning rotor assemblies (rotor and rotor shaft) of one machine must be exchangeable with respect to one another. It therefore happens that the open-end spinning rotor assemblies must be exchanged although the rotor could easily still be used.
Although it is known (German Patent Document DE-A 19 01 453, FIG. 26) to mount to the end of the shaft a hemispherical supporting device made of hard metal, of a diamond or of ceramic material which must also be exchangeable, it cannot be expected that this is a technically useful solution because this measure is definitely too expensive. In this case, it should be noted that, in the case of the extremely high rotational speeds of the rotor which today are at 100,000 min.sup.-1 (100,000 revolution per minute) and more, high requirements must exist with respect to the concentricity of the spinning rotor. It is to be expected that an exchange of such hemispherical supporting devices will require another balancing of the spinning rotor.
It is an object of the invention to provide an open-end spinning rotor assembly of the initially mentioned type which is provided with a simple supporting device that is easy to mount, in which case, as a rule, the mounting of the supporting device does not require another balancing.
In the case of an open-end spinning rotor assembly of the initially mentioned type, this object is achieved in that the supporting element is constructed as a small round plate which, as an extension of the shaft, is mounted on its end face which extends radially with respect to the shaft axis.
Such a small round plate has only a relatively small mass so that it can cause only very minor unbalancing. In addition, it is possible to mount this small plate precisely on the end face extending radially with respect to the shaft axis so that, on the whole, the danger of an unbalancing is very low.
In a further development of the invention, it is provided that the end area of the shaft has a diameter which is reduced with respect to the area used for the radial bearing, and that the diameter of the small plate corresponds at least approximately to the diameter of the end area of the shaft. In this case, a small plate is also only required which is small with respect to its diametrical dimensions and which, because of its shape, can be centered very easily with respect to the end of the shaft.
In a further development of the invention, it is provided that the small plate is held on the end face of the shaft by means of an adhesive or gluing medium. This is a simple mounting method which can be carried out very precisely, particularly in an assembling device or fixture. In this case, under certain circumstances, an exchange of the small plate is also possible by the owner of the machines if this owner has a corresponding assembling fixture. It is also possible to develop these open-end spinning rotor assemblies as exchange components which can be restored in the manufacturing plant and can then be used again.
In a further development of the invention, it is provided that the adhesive or gluing medium forms an intermediate layer between the small plate and the end face of the shaft. The intermediate layer made of the adhesive or gluing medium, which expediently will then also be kept very thin, may serve as a damping element which protects the small plate from wear. In the case of a suitable design of the material of the small plate and/or of the intermediate layer made of an adhesive or gluing medium, it appears possible to increase the durability of the rotor shaft such that it will then correspond to the service life of the rotor so that an exchange of the small plate will then no longer be necessary. In this case, it is expedient for the small plate to be mounted on the end face of the shaft by means of a gluing agent which preferably hardens to a specifiable hardness.
In the case of another development, it is provided that the small plate is vulcanized to the end face of the shaft. Also in this case the hardness of the intermediate layer will be adjustable to the desired values.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.